Jet aircraft typically include one or more engines that may generate high levels of noise. For example, a fan case within a housing secured to a wing of an aircraft typically generates noise. Often, engine housings include one or more sound dampening structures that are used to absorb at least a portion of the noise generated by components of an engine. For example, an acoustic inlet barrel may be positioned at or proximate to an inlet of the engine housing upstream from a fan case.
Known acoustic inlet barrels are formed of composite materials, such as carbon-reinforced plastics, that are sandwiched around an acoustic core, which may include a porous foam material. Each acoustic inlet barrel is generally formed of multiple pieces. For example, each acoustic inlet barrel may be formed of two or three pieces that are secured together through fasteners, such as bolts. Bulky bolt flanges are formed on the pieces and used to connect the pieces together with the separate and distinct fasteners. However, the bolt flanges add mass to the acoustic inlet barrel. Moreover, the process of securing the pieces together is generally labor and time intensive. Further, because each acoustic inlet barrel is formed from separate and distinct pieces that are secured together through fasteners, the integrity of the formed acoustic inlet barrel may be compromised through joints, seams, and the like between the pieces. Also, the areas on and around the joints, seams, and the like may exhibit less than optimal acoustical characteristics.
Certain known acoustic inlet barrels are formed through composite sandwich structures. A foaming adhesive is used to connect portions of a composite sandwich structure together. For example, the composite sandwich structure may include a panel that is wrapped around a tool. Ends of the panel form a connection joint. The adhesive is positioned at the connection joint. During a curing process, the adhesive reacts and adheres to the ends of the panel. As the adhesive cools and hardens during or after the curing process, the hardened adhesive forms a structural bond that securely connects the ends of the panel together.
After the forming process, the connection joint is inspected to ensure the integrity of the adhesive connection between the ends of the panel. A core splice gap width represents criteria for verifying the integrity of the adhesive connection. However, the forming process often renders an inspection of the connection joint difficult, as the adhesive connection may be hidden by composite skins that have been cured to the core.
In a typical foam adhesive splice, a gap between core segments may be subject to bondline depressions, which may form surface depressions in composite skins. In some cases, the depressions may cause the component to be rejected, which then results in considerable rework and/or discarding of the component.
Verifying an acceptable core splice gap width is accomplished by joining segments of core prior to bonding of composite skins. As such, the core splices may be visually verified before being subjected to final composite bonding. However, joining the segments in such a manner limits process flexibility and typically requires a two-step cure process.
Another method of verifying core splice gap width is through radiographic inspection. However, fabricating facilities may not have radiographic equipment readily available. Further, radiographic equipment may be expensive and often requires regulatory approval and certified technicians to operate.
Accordingly, a need exists for a system and method for efficiently, cost-effectively, and reliably connecting portions of a composite material together.